Author: Joshi <rekhajoshm@gmail.com>
Author: Rekha Joshi <rekhajoshm@gmail.com>

Closes #5989 from rekhajoshm/fix/SPARK-7435 and squashes the following commits:

cfc9e02 [Joshi] Spark-7435[R]: updated patch for review comments
62becc1 [Joshi] SPARK-7435: Update to DataFrame
e3677c9 [Rekha Joshi] Merge pull request #1 from apache/master